Dear Lifehacker,
I recently jailbroke my iPhone and installed a boatload of jailbreak apps, and at first everything was going great. After a few days, though, my phone slowed down and now it occasionally even crashes. Is there a way to hunt down the culprits and figure out what's going on?

Sincerely,
Slow Jailbreaker

Dear SJ,
It has long been rumored that jailbreaking your iPhone automatically causes it run slowly, but your jailbreak isn't the culprit. It's some—not all—of the apps you install from Cydia, the App Store for jailbreak apps and tweaks. With that in mind, let's take a look at the ways you can track down the offending tweaks and apps and get your iPhone back into good running shape.

Before we get into digging for apps that are slowing down your iPhone let's start by making sure you're in good shape to begin with. The first thing to do is just reboot your phone and see if that helps (hold down the home and power button until it reboots). If a reboot doesn't work check your memory usage. Jailbreaking doesn't take up much disk space on its own, but the apps you install do. Tap Settings > General > Usage and look at how much storage space you have left. If it's below 1 GB, you probably want to start clearing out apps you don't use or media you don't need.

You might also want to check in Cydia for updates to your apps. Around the time of a new jailbreak, for example, an app or tweak might suck up memory until it's updated to support the new operating system. In Cydia, tap Changes, and if any new versions of your jailbreak apps are available, tap Upgrade.

If you're still experiencing problems, it's time to track down the culprit.

Track Your Available RAM When Using Apps

If your apps are updated and all is well on the the storage front, then it's time to hunt for the culprit. The best way to do this involves watching your phone's available RAM (RAM is sort of like your phone's short-term memory). We'll do this with a jailbreak app called SBSettings.

Open Cydia, search for, and install SBSettings. SBSettings stands for Springboard Settings and allows you to see what's going on under the hood of your iPhone. In our case we're looking at the RAM usage. Once installed, open up SBSettings and tap SB Settings Options > Statusbar Free Mem. You'll now see how much RAM your iPhone has available next to the clock on the status bar.

When you're on the home screen and not doing anything it should show around 250-300 MB of RAM free. When you perform any action or open any app, your RAM will decrease. Play around with a bunch of your newly installed jailbreak apps and see if you see a huge drop in the amount of memory used. If you do, that app is probably the cause of the sluggish behavior. Uninstall it and see if your performance is improved. The same goes for any tweaks or anything else you have installed. For instance, if you're idling and not using any apps and your available memory is still really low, the problem might be in one of the tweaks you have running in the background. These might include Notification Center widgets or home screen tweaks. If nothing is clearly causing a problem, it's time to disable your downloads one by one.

Disable Themes, Custom Animations, and Interface Tweaks One-By-One

If none of the above tips work and your iPhone is still sluggish you have to go through your tweaks one at a time. Fortunately for those who have a lot of apps installed the process isn't totally random.

First off, if you're using a custom skin with the reskinning utility Winterboard you should disable it and see if that clears up the problem. In a lot of cases, especially with older model iPhones, Winterboard can slow down iOS a lot. If that doesn't work, it's time to pop into SBSettings again.

In SBSettings tap Mobile Substrate Addons. Here you'll find a list of tweaks and apps that fundamentally change how your iPhone's operating system works. These might include tweaks that push mail, Activator functions, or anything that changes the look of the operating system. In most cases it's one of these downloads that causes slowdown. Go through each tweak and disable them one at a time to see if your iPhone's performance increases.

If your iPhone is still sluggish then you're remaining option is to uninstall apps one at a time. Open up Cydia, tap Manage > Packages and start going through your list of installed apps. Delete apps you've installed that you suspect might be the problem, reboot, and see if it fixes your phone. Continue this process until you find the culprit.

Unfortunately, tracking down a resource hogging app isn't as easy as popping up an activity monitor and removing anything not working properly. However, the above tips should help you pinpoint the app causing slowdown so you can get rid of it.

Sincerely,
Lifehacker

P.S. Have your own system for tracking down loose cannon jailbreak apps bent on slowing down your iPhone? Share them in the comments.